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Homework Help: Hot Cold body in contact, what happens with heat and temperature?

  1. Aug 17, 2009 #1
    1. The problem statement, all variables and given/known data
    A hot body is brought into contact with a colder body until their temperatures are the same. Assume that no other bodies are around.
    1.Is the heat lost by one body equal to the hear gained by the other?
    2.Is the temp drop of one body equal to the temp increase of the other?

    2. Relevant equations
    No equations needed.

    3. The attempt at a solution
    I am sure that the heat lost by one is equal to the heat gained by the other, as heat is defined as the energy transferred from one body to the other due to a difference in temp.

    But I am not sure if this necessarily implies that the drop in temp of one is equal to the rise in temp of the other?

    Could someone please explain?

  2. jcsd
  3. Aug 17, 2009 #2
    You are correct for the first part!

    For the second part, if I have very large insulated pot of (almost boiling ~100 Celsius) water and put a few ice cubes into it (~0 Celsius), do you think that the equilibrium temperature will be 50 degrees Celsius?

    Think about it -- What's an equation that related temperature change to heat energy? Are the two directly equal or are their other variables that you need to consider in that equation?
  4. Aug 18, 2009 #3

    Okay, this means, that the rise in temp of one will be equal to the drop in temp of the other body, only if their specific heat capacity and mass are the same, right? Otherwise, the drop in temperature might not equal the rise of temperature of the objects.

  5. Aug 18, 2009 #4


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Pretty much. Note that as long as the product, mc, is the same for both, then the temperature drop & increase would be the same.
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